I've had hamstring pain for 10 months. Sometimes the pain is acute and sometimes it is general. There are a few things that definitely make it worse: sitting for long periods of time (like driving or flying). Biking and swimming rarely make it worse while running - especially uphill - makes it worse. I trained for a half Iron Man starting last November and felt the hamstring pain in late-December, early-January. Since then, I've taken a few breaks from exercise but almost immediately the pain returns. In addition to resting, I've done physical therapy. Anyone experience anything like this?